Pilger rolling mill



June 1935, W D 2,005,657

PILGER ROLLING MILL Filed Jan. 25, 1930 4 Sheets-Sheet 1 I Fly 7 /0 1 5 7'4 Q in 4 @mky Jill/[HTOR v RIC/Mk0 LUPW/G arrwnrrmms I R. LUDWIG 2,005,657

4 Sheets-Sheet 2 June 18, 1935.

PILGER ROLLING MILL Filed Jan. 25, 1930 June 18, 1935. R. LUDWIG I PILGER ROLLING MILL Filed Jan. 25 1930 4 Sheets-Sheet 5 as June s, 1935 amass-1" PATENT. OFFICE mesnnoumqmm.

Richard Ludwig, DnsecIdorf Unterrath,

Application raspy- 2'5, 1930, Serial No. 423,449

r In Germany February 7, 1929 20Claims.

This invention is fdr improvements in or re lating to a process and apparatus for the production of. tubes upon a Pilger rolling mill.

In the rolling out of tubes in accordance with 5 the Pilger process, mandrels are used which are not cylindrical, but are shaped with a slight taper so that the same, afterthe' rolling out of a tube, may be more easily withdrawn from the tube.

'I'his'taper of the Pilger mandrel has, however, the disadvantage, that when the Pilger rolls are maintained, at a constant distance from one another, a tubeirolled thereby is cylindrical outside and tapered inside, so that the thickness of the wall at the end of the tube where the rolling process commences is greater thanat the end thereof where the said process finishes. In order to obtain an equal thickness. of the wall over the whole length of the-tube, it is necessary, during the rolling of the tube, to 'control the distance which separates the two Pilger rolls in a manner whichcompensates for the taper ofthe mandrel. This has hitherto been efiected directly by, the operator through the medium of the normal roll adjusting apparatus. 7 I

As the displacement of the rolls by independent adjustments as above described must only amount to a few hundredths of a millimeter, the manipulation of the regulating device of the adjusting apparatus necessitates great skill and attention on the part of the operator. The separate adjustments of the rollsto regulate the distance apart thereof are generally too great or too small,

so that tubes are produced having walls pf marked irregular thickness.

The present invention comprises a process for the production of tubes havinga constant wall thickness upon Pilger rolling mills, characterized by the feed apparatus of the mill being operatively connected to the Pilger r'olls by means.

whereby the two Pilger rolls are automatically moved relatively to one another during the rolling of a tube by an amount.corresponding to the taper of the mandrel. The transmission of the movement of the feed apparatus to the Pilger rolls can be effected in any suitable manner.

In order that the invention may be fully understood reference is directed to the accompanying drawings in which:- v Figure 1 is a sectional side elevation of a'Pilger D rolling mill constructed in accordance with'this invention.

Figure 2 is a sectional plan of Figure 1.

Figure 3isaviewsimilartoFigur 1 ofamod-- ifled form of Pilger rolling mill 'constructed in l accordance with this invention. I

' Figure 6 is a sectional side elevation illustrated in Figure 5, and

Figure ,7 is a plane of Figure 6. Referring toFigures 1 and 2 of the drawings, i, 1 indicate the frame of a rolling mill with Pilger rolls 2, 2 mounted'therein in the usual 10 manner and the upper roll of which can be raised or lowered by means of the screwed spindles 3,

worm wheels I, worms 5. keyed upon a shaft II which may be driven from a source of power, as for example, an electric motor 6. A Pilger man- 5 drel I is arranged to carrya hollowlpom 8 which is to be rolled out, and a driving rod! is provided for imparting a feed movement to the mandrel I and bloom 8 from'a driving apparatus ill in the usual manner. w

- The free end of the shaft II is extended and is arranged to carrymne element l2 of a cone clutch which, during the rolling process of the tube is arrangecl'to be frictionally coupled to the other element It of the clutch by means of a fork l3 engaging therewith and which is connected to a. lever l4 and a weight I5. A key l'l provided upon the shaft 1 I, and a corresponding keyway 1n the clutch element l2 engaging I therewith, permits the latter to be axially displaced along the shaft H'but ensures that the said element and shaft rotate together. The dis-engagementoi the two clutch'elements l2, and I6 is accomplished by lifting the weight 15 through the medium of a cord l8 or any other suitable apparatus.- The clutch element 16 is firmly connected by a hollow shaft I9 to a worm wheel 20 and is rotatably carried in a bearing 2!. A worm 22 is arranged in engagement with the worm wheel '20 and is mounted in fixed rela- 40 tion upon a shaft 23, provided with screw thread of relatively large pitch.

A correspondingly screw threaded nut 25 is mounted upon the screw'threaded' shaft 23 and upon the rolling operation of the tube, is arranged to be displaced along the steeply inclined thread of the shaft 23 in the direction of the arrow Figure 2, by means of an arm- 26 secured to the feed driving apparatus iii. A pin 2'! mounted,

upon the arm 26 is arranged to engage between adjacent teeth 24 provided upon the nut 2'5 and thereby prevents the rotation of the latter.

, The method of operation of the apparatus is as follows:

The clutch elements l2 and I6 are first disenadjusted'by means of the worms 5 to the normal smallest outside diameter of the tube to be rolled. The weight I5 is thereupon dropped and the worm shaft II is coupled to the worm wheel 20. The feed driving apparatus N, with the Pilger mandrel 1 and the hollow bloom 8 supported thereon is then moved towards the roll frame I so that the free end of the Pilger mandrel is disposed between therolls, the arm 26 on the driving apparatus ll! abuts against the nut 25 on the screw threaded spindle 23 and the pin 21 engages between two teeth 24 of the nut and prevents the rotation thereof.

As the process of rolling the tube proceeds the accompanying displacement of the nut 25 along the spindle 23 causes the latter to be retated. This rotation is transmittedby the worm 22, worm wheel 2il','hollow spindle f9, clutch elements l2 and '6, key i1, worm shaft ll, worms 5 and worm wheels I, to the press spindles 3, which raise the upper Pilger roll 2 proportionally to the feed movement of the apparatus l6 and by an amount corresponding to the taper of the Pilger mandrel.

As the described operation of raising the upper roll is distributed uniformly over the whole length of the mandrel, the thickness of the wall of the rolled tube is exactly the same throughout, as compared with the irregular thickness of wall having stepped graduations which is obtained by the previously known processes.

A similar arrangement to that shown in Figures 1 and 2 is illustrated in Figures 3 and 4, in which the lower Pilger roll 2 is automatically raised and lowered while the upper Pilger roll is maintained in a predetermined position.

As in Figures 1 and 2, a Pilger roll frame is provided with a feed driving device as usually ar-v ranged and the numerals I to II! indicate similar parts of the apparatus to those indicated in Figures 1 and 2. A wedge 30 is arranged below each of the two bearings of the lower Pilger roll 2 and is arranged to be displaced by the rotation of a screw threaded spindle 3| engaging therewith.

The spindles 3| are connected by means of pairs of bevel wheels 32 and spindles 33 and 34 with a roller 35 mounted upon the latter. One or more spiral grooves 36 are formed in the roller 35, and one end of an arm 31 secured to the driving apparatus I0 is arranged in engagement with the said groove 36.

With this arrangement, the upper roll is adjusted to the normal diameter of the tube to be rolled in the manner previously described with reference to Figures 1 and 2. When the feed device ID has moved the mandrel and hollow bloom tor-a position-'whera-.-the free. end ofnthe mandrel is disposed between the Pilgerrolls, the

. arm 31 engages with and slides along the spiral groove 36 of the roller 35 and thereby rotates the said roller at a relatively slowspeed.

This rotating movement is transmitted through the spindles 33 and 34, and bevel wheels 32, to the screw threaded spindles 3|, which dis-' place the wedges 30 beneath the bearings of the lower Pilger rolls 2, so that the roll gradually falls as the tube is rolled by an amount corre-' sponding to the taper of the Pilger mandrel.

When a tube has been rolled, a return move ment of the feed driving apparatus In, causes the roller35 to be rotated in thereverse'direction' to that above described by the arm 31 into its initial position and the two wedges 30 together gaged by lifting the weight IS, the rolls are then with the lower Pilger roll are also brought into the initial position thereof.

In Figures 5, 6 and 7, a form of construction is shown in which, as in Figures 3 and 4, a roller 35 is employed provided with a spiral groove 36 and into which latter an arm 31' secured to the feeding apparatus I0 is arranged to extend. The rotation of the roller'35 by the arm 31 as the rolling operation proceeds, istransmitted by a spindle 38 to a worm drive 39-40 and to toothed wheels 4], 42 and 43. The wheels 42 are mounted upon hollow internally and externally screwed sleeve nuts 44 arranged to screw into the frames I. The internal screw threads of the nuts 44 are arranged in engagement with the corresponding externally screwed spindles 3, and it will be observed that the rotation of the spindle 38 during the rolling of a tube, causes the upperPilger roll to be raised, in a manner similar to that described with reference to Figures 1 and 2, by

an amount corresponding to the taper of the '-port a tubular bloom co-axially thereon, rolls carried by the mill, means for feeding said mandrel and bloom between at least one pair of rolls,

the rotation of the nut to move one of a pair of said rolls relatively to the other, and means connecting said nut and said feeding means to move the said roll during a rolling operation by an amount corresponding to the taper of the mandrel.

2. A Pilger rolling mill which comprises in combination a tapered mandrel arranged to support a tubular bloom co-axially thereon, rolls carried by the mill, means for feeding said mandrel and bloom between at least one pair of said rolls. a nut and at least one feed screw operable by the rotation of the nut to move one of a pair of said rolls relatively to the other, and a clutch mechanism between said nut and said feeding means, means connecting said clutch mechanism to said feeding means and means connecting said clutch mechanism and said nut, whereby to move the said roll during a rolling operation by an amount corresponding to the taper of the mandrel.

3. A Pilger rolling mill which comprises in combination a tapered mandrel arranged to support a tubular bloom co-axially thereon. rolls carried by the mill, means for feeding said mandrel and bloom between at least one pair of said rolls, a rotatable screw threaded spindle having a thread of relatively large pitch, a nut arranged in, .,engagement therewith and adapted to be moved by said spindle,- and means operated by said spindle to, move the rolls relatively to one another during the rolling operation.

4. A Pilger rolling mill which comprises in combination a tapered mandrel arranged to support a tubular bloom co-axially thereon, rolls carried by the'mill, means for feeding said mandrel and bloom between at'least one pair of said rolls, a rotatable screw threaded spindle having a thread of relatively large pitch, a nut arranged in engagement with said spindle and adapted to be moved by the feeding means so as to rotate the said spindle, and means operated by said the feeding means'soas to -rotate the .a nut and at least one feed screw operable by spindle to move the rolls relatively to one another during the rolling operation and clutch mechanism between said roll-moving means and said spindle for temporarily disabling sfiid roll-mov ing means.

5. A Pilger rolling mill which comprises in combination a tapered mandrel arranged to support a tubular bloom co-axially thereon, rolls carried by the mill, means for feeding said mandrel and bloom between at least one pair of said rolls, at least one feed screw operable to move one of a pair of said rolls relatively to the other, and an operative connection between said feed screw and the said feeding means to move the said roll during a rolling operation by an amount corresponding to the taper of the mandrel, the said operative connection including a rotatable screw threaded spindle having a thread of relatively large pitch and a nut arranged in engagement therewith and adapted to be moved by the said feeding means so as to rotate the said spindle.

6. A Pilger rolling mill which comprises in combination a tapered mandrel arranged to sup port a tubular bloom co-axially thereon, rolls carried by the mill, means for feeding said mandrel and bloom between at least one pair of said rolls, at least one feed screw operable to move one of a pair of said rolls relatively to the other, and an operative connection between said feed screw and the said feeding means to move the said roll during a rolling operation by an amount corresponding to the taper of the mandrel, the said operative connection including a clutch mechanism and a rotatable screw threaded spindle having a thread ofrelatively large pitch and a. nut arranged in engagement with said spindle and adapted to be moved by the said feeding means so as to rotate the said spindle.

'7. A Pilger rolling mill which comprises in combination a tapered mandrel'arranged to support a tubular bloom co'axially thereon, rolls carried by the mill, means for feeding said mandrel and bloom between at least one pair of said rolls, and an operative connection between said feeding means and at least one of the said rolls for automatically moving the rolls relatively to one another during arolling operation by an amount corresponding to the taper of the mandrel, the said operative connection including a rotatable screw threaded spindle-having a thread of relatively large pitch and a nut arranged in engagement therewith and adapted to be. engaged and moved by the said feeding means so as to rotate the said spindle, the said feeding means being provided with a stop member arranged to engage automatically during a. rolling operation with a projection provided upon the said nut so as to prevent the rotation thereof.

8. A Pilger rolling mill which comprises in combination a tapered mandrel arranged to support a tubular bloom co-axially thereon, rolls carried by the mill, means for feeding said mandrel and bloom between at least one pair of said rolls, and an operative connection between said feeding means and at least one of the said rolls for automatically moving the rolls relatively to one anotherduring a rolling operation by an amount corresponding to the taper of the mandrel, the said operative connection including a clutch mechanism and a rotatable screw threaded spindle having a thread of relatively large pitch and a nut arranged in engagement with said spindle and adapted to be engaged and moved by said feeding means so as to rotate the said spindle, the said feeding means being provided with a stop member arranged to engage automatically during a rolling operation with a projection provided upon the said nut so as to prevent the rotation thereof. y

9. A Pilger rolling mill which comprises in combination a tapered mandrel arranged to support a tubular bloom co-axially thereon, rolls carried by the mill, means for feeding said mandrel and bloom between at least one pair of said rolls, at least one feed screw operable to move one of a pair of said rolls relatively to the other, and an operative connection between said feed screw and the said feeding means to move the said roll during a rolling operation by an amount corresponding to the-taper of the mandrel, the said operative connection including a rotatable screw threaded spindle having a thread of relatively large pitch and a nut arranged in engagement therewith and adapted to be moved by the feeding means so as to rotate the said spindle, the said feeding means being provided with a stop member arranged to engage automatically during a rolling operation with a projection provided upon the said nut so as to prevent the rotation thereof.

10. A Pilger rolling mill which comprises in combination a tapered mandrel arranged to support a tubular bloom co-axially thereon, rolls carried by the mill, means 'forfeeding said mandrel and bloom between at least one pair of said rolls,.at least one feed screw operable to move one of a pair of said rolls relatively to the other,

and an operative connection between said feed screw and the said feeding means to move the said roll during a rolling operation by an amount corresponding to the taper of the mandrel, the said operative connection including a. clutch mechanism and a rotatable screw threaded spindle having a thread of relatively large pitch and a nut arranged in engagement with said spindle and adapted to be moved by the feeding means so as to rotate the spindle, the

said feeding means being provided with a stop member arranged to engage automatically'during a rolling operation with a projection provided upon the said nut so as to prevent the rotation thereof.

11. A Pilger rolling mill which comprises in combination, a tapered mandrel adapted to support a tubular bloom co-axially thereon, rolls carried by said mill, means for feeding said mandrel and bloom between at least one pair of said rolls, ascrew threaded spindle of relatively large pitch,

an operative connection between said feeding means and said spindle, means operatively'connected to at least one of said rolls. for automatically moving the rolls relatively to one another mandrel, said operatively connected means-being driven by said spindle during a rolling operation.

12. A Pilger rolling mill which comprises in combination, a tapered mandrel, adapted to support a tubular bloom co-axially thereon, rolls carried by said mill, means for feeding said mandrel and bloom between at least onefpair of said rolls, a screw threaded spindle of relatively large pitch, an operative connection between said feed ing means and said spindle, clutch mechanism connected to at least one of said rolls for automatically moving the rolls relatively to one another by an amount corresponding to the taper of the mandrel, said clutch mechanism being drivenby said'spindle during a rolling operation.

13. A Pilger rolling mill which comprises in combination, a tapered mandrel arranged to support a tubular bloom co-axially thereon, rolls by an amount corresponding to the taper of the carried by said mill, means for feeding said mandrel and bloom between at least one pair of said rolls, at least one feed screw operable to move one of a pair of said rolls relatively to the other, a screw threaded spindle of relatively large pitch adapted to be rotated during a rolling operation, an operative connection between said feed screw and said screw threaded spindle, means arranged to engage the thread on said spindle and t-o'be moved by said feeding means to operate said feed screw and cause relative and automatic movement between said rolls by an amount corresponding to the taper of the mandrel.

- 14. A Pilger rolling mill which comprises in combination, a tapered mandrel arranged to support a tubular bloom co-axially thereon, rolls carried by said mill, means for feeding said mandreland bloom between at least one pair of said rolls, at least one feed screw operable to move one of a pair of said rolls relatively to the other, a screw threaded spindle of relatively large pitch adapted to be rotated during a rolling operation, clutch mechanism between said feed screw and said screw threaded spindle, means arranged to engage the thread on said spindle and to be moved by said feeding means to operate said feed screw and cause relative and automatic movement be-, tween said rolls by an amount corresponding to the taper of the mandrel.

15. A Pilger rolling mill which comprises, in combination, a tapered mandrel arranged to support a-. tubular .bloom coeaxially. thereon rolls carried by the mill, means for feeding said mandrel and bloom between at least one pair of rolls, a nut and at least one feed screw operable on the rotation of-said nut to move one of a pair of said rolls relatively to the other, a screw threaded spindle of relatively large pitch adapted to be rotated during a rolling operation, an operative connection between said nut and screw threaded spindle, and means arranged to engage a thread on said spindle and to be moved by said feeding means to operate said feed screw and cause a relative and automatic movement between the said rolls'by an amount corresponding to the taperof the mandrel.

16. A Pilger rolling mill which comprises, in combination, a tapered mandrel arranged to support a tubular bloom co-axially thereon, rolls carried by the mill, means for feeding said mandrel and bloom between at least one pair of rolls, a nut and at least one feed screw operable on the rotation of said nut to move one of a pair of said rolls relatively to the other, a screw threaded spindle of relatively large pitch adapted to be rotated during a rolling operation, clutch mechanism between said nut and screw threaded spindle, and

4 means arranged to engage a thread on said spindle and to be moved by said feeding means to operate said feed screw and cause a relative and automatic movement between the saidrolls by an amount corresponding to the ta er of the mandrel.

17. A Pilger rolling mill comprising a tapered mandrel arranged to support a tubular bloom coaxially thereon, rolls carried by the mill, means to feed said mandrel and bloom between said rolls,

clutch mechanism between said feeding means and a least one of said rolls, means connecting said clutch mechanism with said feeding means, and means for taking the motion which said clutch mechanism derives from said feeding means and moving the rolls relatively to one another during the rolling operation by an amount corresponding to the taper of the mandrel.

18. A Pilger rolling mill comprising a tapered mandrel arranged to support a tubular bloom coaxially thereon, rolls carried by the mill, means to feed said mandrel and bloom between said rolls, a feed screw operative to move at least one of said pair of rolls, and means connecting said feeding means to said feed screw for automatically moving the rolls relatively to one another during a rolling operation by an amount corresponding to. the taper of the mandrel, said connecting means operating during the forward movementof the tube while the tube is not under the influence of the rolls. 7

19. A Pilger rolling mill comprising a tapered.-

mandrel arranged to support a tubular bloom coaxially thereon, rolls carriedby the mill, means to feed said' mandrel and bloom between said'rolls, clutch mechanism between said feeding means and at least one of said rolls, means connecting said clutch mechanism with said feeding means and means including -a feed screw for taking the motion which said clutch mechanism, derives from said feeding means and moving the rolls relatively to one another during the rolling operation by an amount corresponding to the taper of the mandrel.

' 20. A Pilger rolling mill which comprises in combination a tapered mandrel arranged to sup port a tubular bloom coaxially thereon, segmental Pilgerrolls carried by the mill, means to move the mandrel forward and backward between the rolls, a limited extent on a working and return stroke,'means operating predeterminedly to give a greater throw to said forward stroke to progress said mandrel and tube through said rolls and to successive treatments thereby, ing one of said rolls with respect to the other, and means for. positively connecting said mandrel, progressing means to said roll adjusting means to automatically change the roll pass in an amount corresponding to the progressing taper of the mandrel.

RICHARD LUDWIG.

means for adjust- 

